This invention relates generally to thermostats and in particular to a cradle for switch means supporting use therein and a method of manufacturing such cradle.
In the past, thermostats operable in both a heating mode and a cooling mode utilized various types of cradles or brackets for supporting or mounting a pair of switch means, such as mercury switches for instance. At least some of these past thermostats utilized a spirally wound bimetal element for sensing the temperature of a given space in which the thermostats were adapted to be located, and a cradle having a pair of the mercury switches supported thereon was attached to the bimetal element for conjoint movement therewith not only in response to the temperature of the given space but also to adjusted positions in response to manual movement of a temperature selector arm drivingly associated with the bimetal element. Of course, in the heating mode operation and the cooling mode operation of the thermostat, the mercury switches were responsive to movement of the bimetal element to control the operation of a system associated with the given space for conditioning the temperature thereof. Two of such past thermostats are illustrated in applications Ser. No. 750,277 filed Dec. 13, 1976 (now U.S. Pat. No. 4,115,751 issued Sept. 19, 1978) and Ser. No. 750,280 filed Dec. 13, 1976 (now U.S. Pat. No. 4,114,681 issued Sept. 19, 1978) which are also specifically incorporated by reference herein.
At least some of the past cradles were provided with a pair of generally planar leg portions formed of a thin metallic material and having opposite ends, respectively. The mercury switches were mounted by various suitable means intermediate the opposite ends of the cradle leg portions, and one of the adjacent opposite ends of the cradle leg portions were pivotally interconnected so that the mercury switches could be positioned or tilted, i.e. with respect to the horizontal, in order to predetermine the trip or switching points thereof. Further, in some of the past cradles, various adjusting mechanisms, such as for instance threaded adjusting screws or eccentric screws or the like, were associated with the cradle leg portions between the other of the opposite ends thereof and operable to effect adjusting pivotal movement of the cradle leg portions to adjusted positions in order to attain the predetermined switching points of the mercury switches respectively carried on the cradle leg portions. However, one of the disadvantageous or undesirable features of such past cradles is believed to be that, at least in some instances, they may have become misadjusted through usage so as to deleteriously affect the predetermined trip points of the mercury switches carried thereby. Another disadvantageous or undesirable feature of such past cradles is believed to be that they could be adjusted subsequent to factory calibration in order to alter the predetermined switching points of the mercury switches carried thereby so as to affect the heating mode operation and cooling mode operation of the thermostat. Still another disadvantageous or undesirable feature of the past cradles is believed to be that the adjusting mechanisms associated therewith for predetermining the switching points of the mercury switches were somewhat complex which, of course, results in an analogous economic disadvantageous feature.